| 摘要 |
A motor driven hammer is described comprising a housing (3), a motor (9) having a motor shaft (11) and being arranged in the housing (3), a hammer mechanism including a cylinder (17) in which a ram (23) is arranged the ram being slidable along a longitudinal axis (L) of the cylinder (17), and a tool holder (15) which may support a tool bit so that the tool bit is aligned with the longitudinal axis (L) of the cylinder (17), wherein the motor (9) is coupled with the hammer mechanism, so that rotation of the motor shaft (11) results in a reciprocating movement of the ram (23) within the cylinder (17), the ram (23) applying impacts on a tool bit supported by the tool holder (15) during the reciprocating movement. Further, the ram (23) is made of a paramagnetic or ferromagnetic material or comprises a permanent magnet and a coil (47) is arranged within the housing (3) adjacent to the cylinder (17) so that the coil (37) applies a force in the direction of the longitudinal axis (L) on the ram (23) if a current is applied to the coil (47). |
